1. Field of the Invention
This invention relates to agricultural cultivating tools which are attached to a standard or other tool support portion of a cultivating implement and, more particularly, to an improved cultivating sweep. Specifically, the present invention relates to an improved sweep design which permits uniform wear across the face of the sweep without narrowing the overall width of the sweep or blunting its point.
2. Description of the Prior Art
A wide variety of cultivating tools have evolved over the years for the tillage of soil. Such tools have been designed for a variety of purposes and soil conditions. Wing sweeps evolved for the purpose of performing the function of cutting off or uprooting weeds as well as for breaking up or mulching the surface of the soil in order to conserve soil moisture.
Wing sweep designs generally include a forwardly pointed body which is attached to a cultivating implement of some sort. Such wing sweeps include a pair of blades or wings which extend rearwardly from opposite sides of the body, or in some cases, a single blade or wing on one side of the body only. The body wings have customarily been provided with cutting edges extending rearwardly from the point of the body and along the outer front edges of the wings, the wings and the body being shaped so that the cutting edges are in the pattern of a "V" with the apex of the "V" being at the point. In many types of such sweeps, the V-pattern edge lies substantially in a plane. In the transverse direction, the wing or blade inclines upwardly and inwardly from the edge.
Such sweeps are adapted for use on cultivator implements that are drawn by tractors whereby they are propelled at a high forward velocity through the soil and subjected to substantial mechanical strains. Examples of wing sweep designs which exist as part of the prior art are disclosed in U.S. Pat. Nos. 2,351,388, 2,595,353, 2,704,499 and 3,038,424. As can be seen from these particular prior art patents, the V-shaped wing sweep design as described above is common. The basis for this V-shape design resides in the modern approach to sweep cultivation wherein evaporation of moisture from soil can be reduced if a layer of the surface soil is sliced or sheared off from the underlying soil and then replaced with a minimum of soil agitation with the soil surface being left relatively level without furrows and ridges. The sweep designs of the above-referenced prior art patents contribute to this concept of cultivation and mulching in various ways and include wings that diverge rearwardly in a "V" so that the soil flows rearwardly over the body of the sweep and falls by gravity downwardly between the stem and wings and is not thrown or plowed violently toward the sides. The soil is thus replaced on the ground surface between the wings rearwardly of the sweep and avoids the plowing of a furrow as in older type designs.
Unfortunately, there are some disadvantages to the standard V-shaped wing sweep design as disclosed in the referenced patents. More specifically, a common problem is that since the tip or nose of the sweep is the first point of penetration into the soil and receives the brunt of the wear as the sweep is pulled through the soil, the tip will generally wear faster than the rest of the sweep wing portions. Thus, in the V-shape designs, the nose or tip of the sweep tends to flatten to a very blunt shape. When this occurs drawing of the sweep through the soil can become very difficult since the tip is not sufficiently sharp to cause easy initial separation of the soil and penetration of the sweep through the soil. Another wear characteristic of the existing sweep designs is that such sweeps also tend to wear faster at the distal tip portions of the wings as opposed to the center of the wings. This wearing of the end portions of the wings tends to reduce the width of the sweep during its lifetime thus narrowing the path which the sweep makes through the soil. Since the purpose of the sweep is to shear as much surface soil as possible at one time, this narrowing of the sweep reduces the effectiveness and efficiency of the cultivating tool carry the sweep or a plurality of such sweeps.
Finally, sweeps have incorporated a cutting edge inclined to the surface of the ground in order to increase the penetration and cutting capability of the sweep. In order to increase the angle of inclination to the ground, the rear portions of the wing members have generally been designed to be uplifted relative to the ground surface as in U.S. Pat. Nos. 2,352,388 and 2,704,499. A problem with such uplifting of the rear portion of the sweep is that while it will achieve better penetration into the ground, the elevation of the rear portion of the sweep will tend to increase the agitation of the soil. This is an undesirable characteristic according to more modern cultivation techniques. Consequently, there is still a need for a wing sweep design which provides efficient penetration into the soil with minimum agitation of the soil so as to achieve the desired shearing of the soil. Moreover, there is still a need for such a tool which will not only perform the referenced function efficiently but will wear evenly so as to provide maximum efficiency of use throughout the entire life of the wing sweep and which will not wear unevenly so as to bring about premature replacement of the wing sweep.